For reasons of both comfort and security, ventilation and/or cooling of seats, for example in vehicles, is used. The driver's seat, as well as the other seats in the vehicle, may thus be arranged to be cooled by means of special cooling devices, for example in the form of electrical Peltier elements, or by means of a fan that blows on the current surface, or by a combination of these devices. Such a cooling element or fan may be placed in the seat or in the backrest of a seat when it is manufactured. Further, the cooling element or the fan may be connected to a current supply unit that supplies current. The control systems according to previously known technology are of the time control type, i.e. they have pure timer functions, which during certain predetermined time periods control the cooling element to a suitable temperature and the fan to a suitable number of revolutions.
A problem with previously known cooling devices relates to the desire that the seat have an accurately adjusted temperature and dryness on its surface, i.e. on the surface that the traveller in the vehicle senses. For this purpose, the temperature of the cooling element and/or the intensity of the fan may be controlled by means of a sensor unit, e.g. a temperature sensor that is arranged in the seat and that is connected to a control unit. By means of the detector unit and the control unit, the available temperature may be detected. The control unit also comprises current feeding circuits, which e.g. may be based on transistor or relay technology, for feeding current to the cooling element and/or the fan.
Although these previously known systems normally provide reliable cooling and dryness on the surface of a vehicle seat, they are, however, afflicted with certain disadvantages. Such disadvantages relate to the fact that previously known systems, whether timer controlled or manually controlled, and with a cooling element and a fan, provide for a rather uncontrolled cooling and drying of the seat, due to the fact that the cooling by means of the cool airflow almost exclusively takes place by convection, which may lead to local over-cooling of the user which in itself is a health hazard.
A further disadvantage with previously known systems is that a warm and damp user receives cold air directly on the body, which during the drying of the seat and the user may be sensed as cold and damp, and thus unpleasant, by the user. Even if the cooling does not take place by means of blowing of the air directly on the body, but bye means of conductive cooling of the seat, a cold and damp surface may be sensed as unpleasant.
A further disadvantage with previously known systems is that the quick cooling of the seat affects the material of the seat negatively in such a way that the material of the seat becomes less comfortable at low temperatures.
Further disadvantages with previous systems is that a control device with special sensors for a cooling device for a seat occupies significant space and is expensive.
One object of the present invention is thus to provide enhanced cooling, drying, temperature control and ventilation of a vehicle seat comprising a cooling device, where the disadvantages stated above are eliminated and which provides a surface temperature and surface dryness which, during adjustment, becomes more comfortable for the traveller.